The so-called single or one time use cameras, have become increasingly popular with the consuming public. These cameras include a lighttight plastic camera body containing a supply of film which is exposed by the consumer. The camera body and the contained film is then returned in its entirety to the photofinisher who removes the film for processing.
It is beneficial in terms of cost and time for the photofinisher to easily remove the film from the camera in normal light conditions, therefore single use cameras are of the prewind type in which a photographic filmstrip, such as from a 35 mm film magazine is first prewound into an unexposed film roll so that the film is advanced back into the lighttight magazine as exposures are taken by the consumer. The lighttight magazine can then be removed by the photofinisher under ambient lighting conditions.
In the normal production of typical single-use or one-time use cameras, such as those manufactured by Eastman Kodak Company and Fuji Film Photo Ltd., among others, the 35 mm film cartridge has a leader portion of a contained filmstrip protruding from the body of the cartridge. This leader portion can then be cinched up to a takeup spool after the remainder of the camera has been completely assembled. The camera is then lighttightly sealed and a winding mechanism, such as a motor, engages an end of the take-up spool in order to prewind the film onto the take-up spool by rotating the spool and thereby pulling the film from the cartridge. This prewinding procedure allows the filmstrip to be assembled into the camera in ambient light. Such a procedure is described in U.S. Pat. No. 4,972,649, among others.
With the advent of so-called "thrust" type (often referred to as APS) film cartridges, however, the procedure of cinching up the leader portion to a takeup spool for prewind or initially for film advance is not required. In the design of this type of cartridge, such as described in U.S. Pat. No. 5,359,378, among others, there is no protruding leader of the contained filmstrip existing outside of the cartridge.
Rather, an active light lock which can selectively be opened or closed maintains the film contained within the cartridge from being fogged by ambient light. To advance the filmstrip out of the cartridge, the active light lock must first be opened which opens a film exit door of the cartridge and permits film to be thrust from the confines of the cartridge by rotation of a film spool contained within the cartridge.
The prewinding of film, therefore, requires the opening of the light lock prior to thrusting the film from the cartridge across the exposure gate and onto a take up spool or roll core which must be accessed in some way to pull the remainder of film from the cartridge. This necessitates a need to prewind film under limited light conditions, that is, in a darkroom. In addition, and though thrust cartridges eliminate the need to manually cinch up the protruding leader, the thrusting mechanism is not intended for the complete prewinding of a filmstrip from a cartridge.
Japanese Kokai 6-130568A entitled: FILM LOADING METHOD FOR THRUST TYPE CARTRIDGES filed Nov. 16, 1992 describes apparatus and a method for prewinding film in a single use camera using a thrust-type cartridge which like conventional single use cameras requires a spool or mandrel to load the film into the film roll chamber. It would be beneficial, however, to provide an effective means for prewinding both thrust and conventional type film cartridges which obviates the need for a take-up spool or other take-up means in the film roll chamber.